The three options are: bcmc, from Balucinska-Church & McCammon
(1992; Ap.J.400, 699) with a new He cross-section based on (1998; Ap.J. 496,
1044); obcm, as
bcmc but with
the old He cross-section, and, vern,
from Verneret. al. (1996 Ap.J.). This changes the cross-sections in use for all
absorption models with the exception of wabs.